Spatial and demographic heterogeneity in excess mortality in the United States, 2020-2023: a multimodel approach.

In this study, we assessed the overall impact of the COVID-19 pandemic in the United States between 2020 and 2023 through estimates of excess all-cause mortality. Monthly mortality rates over a 19-year period, stratified by age, sex, and state of residence, were used to predict expected mortality for the pandemic years. A combination of models-2 timeseries, a spatial random-effects and a generalized additive-was used to better capture uncertainty. Results indicate that the national excess mortality for the United States decreased in 2023 to 157 000 (95% prediction interval: 35 000-282 000) from 502 000 (436 000-567 000), 574 000 (484 000-666 000) and 377 000 (264 000-484 000) during the years 2020-2022, respectively. Unlike in previous years, deaths with COVID-19 as the underlying cause of death possibly accounted for all excess deaths during 2023. While for the older age groups (>75 years), the year 2020-before vaccines were available-had the highest excess mortality rate, and the 2 younger age groups had the highest excess mortality in 2021. In each age group, women were estimated to have consistently lower excess mortality than men. West Virginia had the highest age-standardized excess mortality among all states in 2021 and 2022. Our findings demonstrate the value of a multimodel approach in capturing heterogeneity in excess mortality.